Method of making laminated glazing units

Abstract

A method of making a laminated glazing unit having an interfacial coating on a laminated ply includes depositing the coating on the laminted ply and then removing a peripheral portion of the coating. Specifically, the peripheral portion of the coating is exposed to a laser beam of sufficient power to remove the coating. The exposure time and power level are controlled to avoid damage to the underlying substrate. Subsequently, the coated substrate ply is laminated to a ply of PVB or other flexible polymeric laminating material. A substantially direct laminating bond is formed between the laminating ply and the surface of the substrate ply in the peripheral area from which the coating has been removed. The peripheral seal thus formed is environmentally durable and protects the interior of the interface from degradation due to progressive edge corrosion and the like.

We claim: 
     
       1. A method of making a laminated glazing unit, which method comprises the steps of: depositing a substantially transparent electrically conductive coating on a surface of a substantially transparent and substantially self-supporting substrate ply;   exposing a selected portion of said coating on an underlying area of said surface proximate to the periphery of said substrate glazing ply to a laser beam, exposure duration and laser beam power being sufficient to substantially remove said selected portion of said coating from the underlying area of said surface; and   laminating substantially the entire portion of said surface with said coating thereon, including the area thereof from which said coating has been removed, to a substantially transparent and flexible polymeric laminating ply.   
     
     
       2. The method of making a laminated glazing unit as in claim 1 wherein a third ply is laminated to the flexible polymeric laminating ply opposite the substrate ply glazing. 
     
     
       3. A method of making a motor vehicle windshield comprising the steps of: depositing a transparent, electrically conductive film stack onto a surface of a transparent, substantially self-supporting substrate ply;   substantially removing said electrically conductive film stack from a zone extending around the entire periphery of said surface by exposing it to a laser beam; and   laminating said surface with said electrically conductive film stack thereon, including said zone from which said electrically conductive film stack has been substantially removed, and a substantially self-supporting second ply to opposite surfaces of a laminating ply substantially transparent and flexible.   
     
     
       4. The method of making a motor vehicle windshield as in claim 3 wherein the substrate ply and the second ply each is glass. 
     
     
       5. The method of making a motor vehicle windshield as in claim 3 wherein the laser beam is produced by an excimer laser. 
     
     
       6. The method of making a motor vehicle windshield as in claim 5 wherein said laser beam has an average power of about 75 watts. 
     
     
       7. The method of making a motor vehicle windshield as in claim 3 wherein the electrically conductive film stack is suitable for electrically heating the windshield. 
     
     
       8. The method of making a motor vehicle windshield as in claim 3 wherein the electrically conductive film stack is suitable for solar load reduction. 
     
     
       9. The method of making a motor vehicle windshield as in claim 3 wherein the film stack comprises a film of silver sandwiched between a pair of dielectric films. 
     
     
       10. The method of making a motor vehicle windshield as in claim 9 wherein the dielectric films are zinc oxide. 
     
     
       11. The method of making a motor vehicle windshield as in claim 3 wherein the laminating ply is polyvinyl butyral. 
     
     
       12. The method of making a motor vehicle windshield as in claim 3 wherein said laminating is performed by application of heat and pressure. 
     
     
       13. The method of making a motor vehicle windshield as in claim 3 where said film stack is deposited by sputter coating individual films of the film stack. 
     
     
       14. A method of making a motor vehicle windshield comprising the steps of: sputter coating a transparent, electrically conductive film stack onto a surface of a glass substrate ply;   substantially removing the electrically conductive film stack from a peripheral zone about 0.06 to about 0.125 inch wide extending around the entire periphery of the surface by exposing the film stack in the peripheral zone to a laser beam of about 75 watts average power and about 248 nm wavelength; and   laminating the substrate ply, including the peripheral zone of the surface thereof, and a second glass ply to opposite sides of a laminating ply of polyvinyl butyral.